Stop event enter in a infinite hook call at node_save

To detect the insert/update of a case and as a result the change of status for a case we use nodeapi that call the _casetracker_time_autostop_status_change function. This ensure that when a user change the status for one of the defined in the autostop status the Timer is stopped. But when the function _casetracker_time_autostop_status_change call to the hook cttime_stop that in some circumstances call to a node_save to make changes to the node.

This enter in an infinite hooks call that in some environments raise a segmentation fault. The autostop functionality doesn't make much sense in nodeapi events considering that at Case Tracker status changes are mainly updated via comment form and observing that events in hook comment is enough to the functionality.